I fired up a debian live USB on my T60 yesterday to do some testing. At some point networkmanager disabled wifi for no discernible reason and would not bring it back up. After a few minutes I gave up and plugged in the Ethernet cable. The applet was still frozen and didn't acknowledge that it was connected, but I was online again.
That same machine normally runs Gentoo, where I use the standard netifrc initscripts, wpa_supplicant and dhcpcd to control networking. Everything about that setup works perfectly 100% of the time.